Retaining pin and bearing assembly

ABSTRACT

An elongated retaining pin having offset end portions allows a bearing assembly to be loosened and easily removed. During operation, the retaining pin is held in position. When the bearing is to be disassembled, the retaining pin is rotated to loosen the bearing assembly.

United States Patent Crow RETAINING PIN AND BEARING ASSEMBLY Inventor:Morgan L. Crow, Dallas, Tex.

Assignee: Dresser Industries, Inc., Dallas, Tex.

Filed: Nov. 5, 1970 Appl. No.: 87,134

US. Cl. ..308/8.2, 175/364, 175/372 Int. Cl. ..E2lb 9/10, E2lb 9/36,E02f 15/44 Field of Search ..308/8.2, 207 R, 189 R;

References Cited UNITED STATES PATENTS Dallerup ..175/364 [4 1 Dec.12,1972

3,054,466 9/1962 Wagnon et al..' ..l75/342 X 1,791,767 2/1931 Stokes..175/364 X 1,848,404 3/1932 Abegg ..175/342 3,203,492 8/1965 Lichte..175/355 3,612,197 10/1971 Motoyama ..175/364 Primary Examiner-David H.Brown Attorney-Robert W. Mayer, Thomas P. Hubbard, Jr., Daniel Rubin,Raymond T. Majesko, Roy L. Van Winkle, William E. Johnson, Jr. and EddieE. Scott [5 7] ABSTRACT An elongated retaining pin having offset endportions allows a bearing assembly to be loosened and easily removed.During operation, the retaining pin is held in position. When thebearing is to be disassembled, the retaining pin is rotated to loosenthe bearing assembly.

5 Claims, 7 Drawing Figures PATENTED v v 3 7 05, 7 5 0 sum 1 or 4 FIG. I

F IG. 7 INVENTOR MORGAN L. CROW ATTORNE Y PATENTED DEC 1 2 I972 SHEET 21F 4 FIG. 2

MORGAN L. CROW PATENTEnnimmz 3.705.750

sum 3 or 4 FIG. 4

INVENTOR MORGAN L. CROW ATTORNEY PATENTED DEC 12 I972 SHEET 8 0F 4 FIG.6

INVE TOR MORGAN L. CRO

A TTORNE Y RETAINING PIN AND BEARING ASSEMBLY BACKGROUND OF THEINVENTION The present invention relates to an improved bearing assemblyand more particularly to a retaining pin that allows the bearingassembly to be easily assembled and disassembled. The bearing assemblyof the present invention includes an outer bearing element and an innerhollow cylindrical bearing shell. A retaining pin is positioned in thecenter of the inner hollow cylindrical bearing shell and mounted betweena pair of support arms. An important requirement of the bearing assemblyis that it must be easy to assemble. In addition, the bearing assemblymust lock firmly in place during operation. The bearing assembly must beeasy to disassemble. The bearing assembly generally operates undersevere conditions and may be subject to corrosion and high amounts ofstress.

Large diameter earth boring bits and certain track vehicles operateunder exposure to a corrosive fluids, highly abrasive conditions,temperature extremes and high loads. When it becomes necessary todisassemble the bearing assemblies, difficulties are often encounteredin that the parts are wedgedtightly together and may be heavilycorroded.

DESCRIPTION OF THE PRIOR ART In US. Pat. No. 3,203,492 to C. L. Lichte,patented Aug. 31, 1965, a large hole earth boring drill bit is shown.This bit includes a number of relatively small rolling or rotatablecutters mounted on the bit head. The rolling cutters are mounted betweena pair of support arms and held in place by a retaining pin. Theretaining pin is positioned in the central opening of a hollow bearingelement. The cutters rotate about the bearing element. The bearingelement includes portions adapted to fit in engagement with recesses inthe support arms. The portions of the bearing element and the recessesin the support arms wedge into tighter interlocking engagement uponrelative movement in one direction.

Summary of the Invention The present invention provides a bearingassembly with a retaining pin having offset end portions. The bearingassembly is securely locked into position during operation and is easilyremoved to facilitate replacement of parts. The bearing shell includesportions adapted to engage a recess in the support arms and wedge intotighter engagement upon rotation in one direction. The pin is locked ina first position during operation. When the bearing is to bedisassembled, the pin is released and rotated. This loosens the bearingshell and allows the assembly to be removed.

It is therefore an object of the present invention to provide animproved bearing assembly.

It is a still further object of the present invention to provide abearing assembly that may be easily removed.

It is a still further object of the present invention to provide a pinhaving offset end portions.

The above and other objects and advantages of the present invention willbecome apparent from a consideration of the following detaileddescription when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a large diameter bitincluding a multiplicity of rotatable cutters.

FIG. 2 shows the saddle and cutter of an earth boring bit.

FIG. 3 shows a pin for retaining the bearing assembly in position.

FIG. 4 is an end-view of another embodiment of the present invention.

FIG. 5 is an end view of still another embodiment of the presentinvention.

FIG. 6 is a view, partially in section, of a bearing assembly of thepresent invention.

FIG. 7 is another embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION Referring now to FIG. 1, a largediameter earth boring bit is shown generally at 10. A pair of rotatablecutters l1 and 12 are positioned next to the central shaft 13 andmounted in a pair of saddles 14 and 15. At least two cutters aregenerally used at a given radius about the center to insure a balanceddrilling bit and a smooth drilling operation. Saddles l4 and 15 aremounted on central shaft 13. The saddles l4 and 15 allow the cutters tobe easily removed and new cutters inserted. A second pair of cutters 16and 17 are located below cutters I1 and 12. Cutters I6 and 17 aremounted in a pair of saddles l8 and 19 mounted on the frame of the largediameter bit 10. They upper end of shaft 13 is threaded to allow the bit10 to be connected to a, rotary drill string (not shown).

The drilling operation generally proceeds by the drilling of a smalldiameter hole approximately the size of shaft 13. The small diameterhole is drilled to an opening and'the small diameter bit removed fromthe drill string. The large diameter bit 10 is then attached to thedrill string and rotated and hydraulically raised along the pilot holethereby enlarging it to the desired size. As bit 10 rotates, cutters ll,12, 16 and 17 contact and disintegrate the formation. The cuttingsurfaces of cutters ll, 12, 16 and 17 should traverse the entire surfaceof the hole being drilled and the saddles and other portions of the bitshould not contact the formations.

Difficulty has been encountered in providing adequate bearing supportfor the rotating cutters of the large diameter bit 10. The bearing mustbe securely locked in place during drilling and must include means forreleasing the cutters from the saddles to allow a change of cutters andbearings.

Referring now to FIG. 2, a rolling cutter 20 similar to those shown-inFIG. 1 is mounted in a saddle 21. The rolling cutter 20 includes inserts22 mounted on its outer surface for disintegrating the earth formations.Saddle 21 includes a pair of individual support arms 23 and 24. Abearing shell 25 is positioned between support arms 23 and 24 and in'theannulus of cutter 20. Two series of rollers 26 and 27 and a series ofballs 28 are positioned between bearing shell 25 and cutter 20 tofacilitate rotation of the cutter. Bearing shell 25 includes dovetailportions 29 and 30 that extend outwardly. Recesses 31 and 32 in thesupport arms 23 and 24 receive the dovetail portions 29 and 30 andprevent the bearing shell 25 from rotating with respect to the saddle21. The cooperation of these two elements is fully described in US. Pat.No. 3,203,492 to C. L. Lichte, patented Aug. 31, 1965. The eccentricdovetail portions 29 and 30 interengage recesses 31 and 32 and wedgeinto tighter interlocking engagement upon relative rotational movementin one direction.

A pin 33 fits through holes in support arms 23 and 24. The pin 33consists of a central body portion 34 and end portions 35 and 36. Thecentral axis of the end portions 35 and 36 are offset from the centralaxis of the body portion 34. A retaining element 37 may be posi tionedin a hole 38 in support arm 24 and extended through a hole 39 in pin 33.This prevents pin 33 from rotating and places the larger body portion 34of pin 33 in the proper position. i

It can be appreciated that as the earth boring bit is exposed to thedrilling environment, the bearing shell 25 will become so firmly lockedinto position that attempts to release it and disassemble the cutter andbearing assemblies will become difficult. This is due to the high stressplaced upon the earth boring bit causing the dovetail portions to becomewedged into a tight interlocking fit and from corrosion and theaccumulation of materials around the areas where bearing shell 25 isconnected to the saddle 21.

This difficulty is overcome by the present invention. When removal ofthe cutter and bearing assembly is desired, the retaining element 37 isextracted. The pin 33 is then rotated to move the extended body portion34 away from the wedged areas of dovetail portions 31 and 32 to loosenthe bearing shell 25. A slot 40 is provided in the end of pin 33 toallow rotary torque to be applied to the pin.

Referring now to FIG. 3, a retaining pin 41 of the present invention isshown. The retaining pin includes an elongated cylindrical body portion42 and smaller cylindrical end portions 43 and 44. The central axes ofcylindrical end portions 43 and 44 are offset from the central axis ofcylindrical body portion 42. A small hole 45 extends through pin 41 andslot 46 is located at the end of pin 41.

Referring now to FIG. 4, an end view of another embodiment of the pin ofthe present invention is shown. The pin 47 has a cylindrical bodyportion with a radius 48. The end portions rather than being regularcylinders include a section 49 having a smaller cross section than thecentral body portion. The section 49 may be circular with a radius 50having its apex offset from the central axis of the main body. Radius 50may or may not be equal to radius 48. The distance from the surface ofsection 49 to the central axis is therefore less than the correspondingdistance from the surface of the adjacent section of the central bodyportion to the central axis.

Referring now to FIG. 5, an end view of still another embodiment of thepin of the present invention is shown. Pin 51 includes a cylindricalbody portion and end portions having a section 52 with a smaller crosssection than the body portion. The distance from a point 53 on thesurface of section 52 to central axis 54 is less than the correspondingdistance from a point 55 on the adjacent section of the body portion tocentral axis 54.

A bearing assembly for use under severe conditions such as on trackvehicles is shown generally at 56 in FIG. 6. An outer rolling member 57is positioned between a pair of support arms 58 and 59. The rollingmember 57 receives the load from the track or other load applyingelement. A bearing shell 60 is positioned between support arms 58 and 59and in theannulus of outer rolling member 57. Two series of rollers 61and 62 and a series of balls 63 are positioned between bearing shell 60and outer rolling member 57 to facilitate rotation. Bearing shell 60includes dovetail portions 64 and 65 that extend outwardly. Recesses 67and 68 in the support arms 58 and 59 receive the dovetail portions 64and 65 and prevent the bearing shell from rotating with respect to thesupport arms. The dovetail portions 64 and 65 are eccentric to thecentral axis of the bearing shell 60 and interengage recesses 67 and 68thereby wedging into tighter interlocking engagement upon relativerotation in one direction.

A pin 69 fits through holes 70 and 71 in support arms 58 and 59respectively. The pin 69 consists of a central body portion 72 and endportions 73 and 74. The central axes of the end portions 73 and 74 areoffset from the central axis of the body portion 72. A retaining element75 may be positioned in a hole 76 in support arm 58 and extended througha hole 77 in the pin 69. This prevents pin 69 from rotating and placesthe larger body portion 72 in the proper position.

When the bearing assembly 56 is to be dismantled, the retaining element7 is extracted. The pin 69 is then rotated to move the body portion 72from the position shown in FIG. 6 and loosen the bearing shell 60. Aslot 78 is provided in the end of pin 69 to allow rotary torque to beapplied to pin 69. A hexagonal hole, or square hole, or other torquetransmitting means can be provided in the end of the pin 69 to rotate itfrom the locked position to the released position.

Referring now to FIG. 7', another embodiment of a pin of the presentinvention is shown generally at 79. The pin 79 includes a main bodyportion 80 and two end portions 81 and 82. The central axis BB of theend portions 81 and 82 is offset from the central axis AA of the bodyportion. A hole 83 in one of the end portions 81 allows pin 79 to belocked firmly in place in the support arms (not shown). The outer end ofend portion 81 is hexagonal to allow rotary torque to be applied to pin79.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. An improved bearing assembly comprising:

a pair of support arms;

an outer rolling member positioned between said pair of support arms,said outer rolling member having a central annulus;

a bearing shell positioned between said pair of support arms in theannulus of said outer rolling member, said bearing shell having acentral annulus;

means on said support arms and means on said hearing shell adapted towedge into tighter interlocking engagement upon relative movement in onedirection for stabilizing said bearing shell;

bearing means between said outer rolling member and said bearing shell;and

a pin positioned between said pair of support arms in the centralannulus of said bearing shell, said pin having an elongated main pinbody with a central axis and end portions extending from the ends of themain pin body, said end portions having central axes offset from thecentral axis of said main pin body 2. The bearing assembly of claim 1including means for selectively preventing said pin from rotating withrespect to said support arms.

3. The bearing assembly of claim 2 wherein said pin includes means forallowing rotary torque to be applied to said pin.

4. An earth boring bit comprising:

a main bit body;

at least one pair of support arms extending from said main bit body,each support arm having a hole and a recess;

a rolling cutter positioned between said pair of support arms, saidrolling cutter having a central annulus;

a bearing shell positioned between said pair of support arms in theannulus of said rolling cutter, said bearing shell having a centralannulus and portions adapted to fit in tapered engagement with saidrecesses in said support arms thereby wedging into tighter interlockingengagement upon relative movement in one direction;

bearing means between said bearing shell and said rolling cutter;

a retaining pin with a central axis positioned between said support armsin the annulus of said bearing shell and extending into the holes insaid support arms, said retaining pin having an elongated main pin bodyand end portions, said end portions having a section wherein thedistance to the central axis is less than the corresponding distancefrom the adjacent sections of the body portion to the central axis; and

means for selectively preventing said pin from rotating with respect tosaid saddle.

5. The earth boring bit of claim 4 including means for allowing rotarytorque to be applied to said pin.

1. An improved bearing assembly comprising: a pair of support arms; anouter rolling member positioned between said pair of support arms, saidouter rolling member having a central annulus; a bearing shellpositioned between said pair of support arms in the annulus of saidouter rolling member, said bearing shell having a central annulus; meanson said support arms and means on said bearing shell adapted to wedgeinto tighter interlocking engagement upon relative movement in onedirection for stabilizing said bearing shell; bearing means between saidouter rolling member and said bearing shell; and a pin positionedbetween said pair of support arms in the central annulus of said bearingshell, said pin having an elongated main pin body with a central axisand end portions extending from the ends of the main pin body, said endportions having central axes offset from the central axis of said mainpin body
 2. The bearing assembly of claim 1 including means forselectively preventing said pin from rotating with respect to saidsupport arms.
 3. The bearing assembly of claim 2 wherein said pinincludes means for allowing rotary torque to be applied to said pin. 4.An earth boring bit comprising: a main bit body; at least one pair ofsupport arms extending from said main bit body, each support arm havinga hole and a recess; a rolling cutter positioned between said pair ofsupport arms, said rolling cutter having a central annulus; a bearingshell positioned between said pair of support arms in the annulus ofsaid rolling cutter, said bearing shell having a central annulus andportions adapted to fit in tapered engagement with said recesses in saidsupport arms thereby wedging into tighter interlocking engagement uponrelative movement in one direction; bearing means between said bearingshell and said rolling cutter; a retaining pin with a central axispositioned between said support arms in the annulus of said bearingshell and extending into the holes in said support arms, said retainingpin having an elongated main pin body and end portions, said endportions having a section wherein the distance to the central axis isless than the corresponding distance from the adjacent sections of thebody portion to the central axis; and means for selectively preventingsaid pin from rotating with respect to said saddle.
 5. The earth boringbit of claim 4 including means for allowing rotary torque to be appliedto said pin.